TR2/3/3A Cylinder head valve springs?

[karls59tr]

Why did Triumph switch from 3 to 2 valve springs per valve? Also why do some people feel that it's OK to reuse valve springs when doing a rebuild ...is it?
In regard to to valve retainers or "keepers:. When I did a head rebuild about 15 years ago I had to send the keepers back to Moss for a better set as the first batch were not made properly and looked like they wouldn't hold. Anyone had that issue?

 

[TR3driver]

They lightened the exhaust valve at the same time (5/16 stem instead of 3/8); so I assume tests showed that the 3rd spring was no longer needed with the lighter valve. I can't find the specs at the moment, but ISTR the inner exhaust spring got stiffer as well.

In theory, it should be OK to reuse valve springs if they are still within specification. Broken springs are not common on TRs (although they do happen more often on Spitfires). But, pretty much every engine I've done, the original springs were weak/sagged from the spec; so I've always replaced them.

Never bought new keepers, so never had a problem with them

 

[CJD]

I measure length and strength of all springs before reusing them. Just for reference, I went through 3 sets of springs last year, and barely kept 1/2 of them...the others had compressed over the years,so did not have enough seat pressure at the installed height. I am rebuilding a street motor, so it will never see high revs for long periods. If youl plan a performance build, I'd lean towards ditching the stock springs for a good set of after-market.

 

[trrdster2000]

I did Isky springs with the lite weight retainers and keepers. Triple cut on the valves and lite push rods, running near red line was never any floating. I ran a high lift cam and I would not recommend for street use. Real lumpy at idle even with 2 inch SU's.

Wayne